FMRI is a non-invasive standard method for to determine blood oxygenation in areas of interest without any significant risks (See document section K6 for standardized and approved methods for conducting fMRI experiments involving human subjects). It is a technique that utilizes magnetic fields and low-energy radio frequencies to visualize brain structures and brain function. Through careful screening procedures subjects with metallic fragments in their body will be excluded from the study since the fMRI magnet exerts a force on ferromagnetic objects. During test day 2 (before and after the weight loss procedure) a canula will be inserted for blood sampling. Blood sampling in this study does not include any other risks for the subjects, other than its usual risk of minor bruising.